#include <stdio.h>

char * mystrcat(char *dest, const char *src)
{
    char *p = dest;
    while(*dest++);
    dest--;
    while(*dest++ = *src++);
    return p;
}

int main()
{

    char a[128] = "asdfdsf";
    char *b = "tt";
    char p[128] = {0};

    printf("%s\n", mystrcat(a, b));

    mystrcat(p, mystrcat(a, b));
    printf("a=%s b=%s p=%s\n", a, b, p);

    return 0;
}